Is time quantized?

[Mighty mouse]

I have just been re-reading Lee Smolin's 'Three Roads to Quantum Gravity'.
He states the fabric of space is not continuous but a lattice, discrete at the Planck scale. String theory has elementary particles, all of which are 'loops' (which only differ in how they they are vibrating) moving through and interacting with each other and the lattice.

On page 62 he states the apparent smoothness of space and time are illusions with the fundamental unit, Planck time, being the minimum unit of it.
So does this mean time is just an illusion in the manner that a film gives an illusion of motion?

He also states a particle can never be at rest due to Heisenberg's uncertainty principle as it would mean it's position and motion were both known. I find that intellectually unsettling.

The book was published in 2000 so is perhaps out of date, any physicists out there?

PS I read a recent letter suggesting the experiments due with the huge accelerator under the Alps to create the conditions of the big bang may by remote chance cause the formation of a black hole. Is this pure Ludditary?

 

[Nik]

Very fuzzy physics...

D'uh, IMHO, things are a bit *fuzzy* in physics just now, with more notions floating about than angels dancing on a Medieval pin-head...

QCD is wonderful to a point, S/G Relativities *almost* meet QCD from other side, but there's a worrisome gap in the middle. That's a matter of some Gravity-- Pun intended. Could be both systems are crude simplifications, could be one, other or both are mere 'epicycles'...

Snag is that none of the major string, loop and/or brane derived hypotheses are currently falsifiable-- CERN *should* weed the field, there's a fair chance that several of the proposals will succumb in the next year or so...

IIRC, Mini Black Holes *should* expire in a blaze of Hawking radiation, the smaller, the faster. IIRC, below a significant mass, they emit faster than they could feed in any medium short of a neutron star, white dwarf core or primordial BigBang singularity...

Also, IIRC, the same 'Black Hole' scare-monger did his best to kill US super-collider with same argument. His court case (!!) failed on basis that natural cosmic rays include frequent whatsits with energies many, many times higher than possible experimental levels. Even a Super-CERN hyper-ring the size of Pluto's orbit would not get close !! As we've had, um, four point something billion years exposure and Earth's still here...

One to watch would be the theorist whose obscure super-symmetry calculations seem to predict several properties of known particles better than QCD. His system may be an arcane version of that 'think of a number' riddle that always gives 2 as answer, or he may just have stumbled on rudiments of a 'Sub-Atomic Periodic Table'. IIRC, there's work in progress to predict further particles and decimal places before CERN's experiments report...

 

[Delvo]

He states the fabric of space is not continuous but a lattice, discrete at the Planck scale... the apparent smoothness of space and time are illusions with the fundamental unit, Planck time, being the minimum unit of it...

There is no definite answer to this yet, so physicists are pondering and debating it and trying to figure out what its implications would be (especially testable ones). There are respected professional physicists on both sides of this question.

He also states a particle can never be at rest due to Heisenberg's uncertainty principle as it would mean it's position and motion were both known. I find that intellectually unsettling.

This one is a pretty solidly established among physicists. Nobody in the profession seriously doubts it; any debate is over its implications and interpretations.

The book was published in 2000 so is perhaps out of date

The things you've mentioned here are not.

I read a recent letter suggesting the experiments due with the huge accelerator under the Alps to create the conditions of the big bang may by remote chance cause the formation of a black hole. Is this pure Ludditary?

It could happen, but it would, at most, just be an interesting thing for them to observe, not a danger. We're only talking about a black hole of a very tiny mass and size; the only thing making it qualify as a black hole would be its density because the size scale is comparable to the size of atoms. To be dangerous, a black hole would need to be many many times more massive than that, and they just don't put that much mass into these experiements. (They couldn't even if they wanted to.)

 

[scalem X]

I'm with Delvo here.

Basically you can't know both the place and time of a quantum particle. Either you project it's curve or you project the time it will pop up. I found it very weird, but I remember my dad explaining it to me and it made sense, I forgot the explanation though.

yeah the time aspect is questioned, but the problem is that time is a concept we created, which means that if we are jumping through time, we need to jump to other times where we also have created the same concept/illusion. Personally I think if it is an illusion, it's static. If it's not an illusion it's linear. The random popping of time and motion would in my opinion lead to ceasing the existence of this phenomenon. Doesn't randomness change into something linear anyway? Take a string of random numbers for example.

As for the back hole. Yeah well black hole is still a theory. After all we can't go and have a look at a black hole and see if it's there, we just assume that is is, just because we can't see anything there.
I doubt we'll create a black hole and the world will implode all of a sudden. would be funny though. I can so see the guy saying:
"John, I have a bad feeling about this."
"Just press the button, dude."

 

[Mighty mouse]

It will be intriguing to see an artist's drawing of the string loop level landscape when isolated. An article on the CERN LHC I found is here: symmetry - December 2007 - Entering Higgs Habitat

Smolin also mentions an Italian Physicist, Giovanni Amelino Camelia, has suggested that a photon travelling through a discrete geometry would over very large distances, if originating from a violent galactic source, suffer slight deviations caused by it's associated wave being scattered by the discrete geometry.

 

[Nik]

Virtual particles etc...

Snag is that any particle travelling for a long time will interact with the not-quite-empty space and magnetic fields between the stars and galaxies. D'uh, even neutrinos can collide, otherwise how can our solar and extra-solar flux be measured ??

Worse, high energy particles will interact with virtual particles...

Unravelling those may leave no clear data to suggest 'new' physics...